Psychology Unit 1- Memory EYEWITNESS TESTIMONY 1
- The effects of misleading info on accuracy of EWT- Loftus (1975)
- Showed film of car accident. Control group- questions consistent with what they had seen e.g. how fast was the car going when it passed the stop sign? Experimental group- questions inconsistent with what they had seen e.g. how fast was the car going when it passed the barn? (when there was no barn) 17% in experimental group- seen barn. 3% control group- seen barn
- Misleading post-event info- absorbed with original memory & now believed there was a barn
- Lab- controlled, realistic material (but still artificial), real life- not pre-prepared. Participants subject to demand characteristics?
- Consent (could not get fully informed consent- DECEPTION)- debriefing v. important
- Potential psychological harm- distressting (although only minor accident and no injuries)
- LOFTUS & ZANNI- "did you see A broken headlight?" "did you see THE broken headlight?"- 17% saw THE broken headlight, 7% saw A broken headlight
- LOFTUS & PALMER- "how fast were the cars going when they hit each other?" smashed bumped collided contacted smashed-highest estimates & reported seeing broken glass contacted- lowest estimates- v. minor
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Psychology Unit 1- Memory EYEWITNESS TESTIMONY 2
Other factors affecting accuracy of EWT
- Reconstructive memory & schema- LIST 1986
- Made list of things expected in shoplifting scenario- asked p's to rate them in how likely to occur. Made video showing 8 shoplifting incidents- included some schema elements. Week later- recall. More likely to recall high prob. events. Often reported high prob. events not even in vid.
- Lab- tried to make vid. realistic- not like real life- pre-prepared. Pilot study used. Consent & debrief.
- Anxiety- LOFTUS & BURNS 1979
- P's outside room- thought listening to real convo. Condition 1- talk of machine failure, man comes out with greasy hands & pen. Conditon 2- heated convo, breaking glass, man with blood on hands & knife. Given 50 pics- identify man. Condition 2- harder to identify man- higher levels of stress- focus on blood and knife. Christianson & Hubinette- survey of people who had witnessed bank robbery. Victims remembered more, bystanders remembered less.
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Psychology Unit 1- Memory EYEWITNESS TESTIMONY 3
Other factors affecting accuracy of EWT
- Age of witness- POOLE & LINDSAY 2001
- Children aged 3-8 - science demonstration at school. Parents- story to read to children at night about science demonstration with novel info. Questioned children about REAL science demonstration at school- incorporated info from story. Asked to think about where info from. Older children- more likely to realise some info was from story- younger children did not. More difficult to eliminate extraneous variables than with artifical stimuli, children- understand & pay attention, consent (parents), familiar people- parents- less susceptible to investigator effects.
- Individual differences- TOMES & KATZ 1997
- More likely to accept misinfo if- generally poorer recall of event, high on measures of imagery vividness, high measures of empathy.
- General problems for research in this area
- Lab- artificial, real life- not pre-prepared, events on film not as shocking/emotional as real life, participants may act to please experimenter, no real consequences (consequentiality), trivial details.
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Psychology Unit 1- Memory EYEWITNESS TESTIMONY 4
How to improve accuracy of EWT
- The cognitive interview technique
- Context Reinstatement (CR): Mentally reinstate the context of the target event. Recall scene, weather, thinking and feeling at time, preceding events.
- Report Everything (RE): Report every detail you can recall even if it seems trivial.
- recall from Changed Perspective (CP): Report as it would have been seen from different viewpoints, not just your own
- recall in Reverse Order (RO): Report in different temporal orders- backwards & forwards in time.
- Police generally use CR & RE.
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